VOLUME 16 NUMBER
6 November/December 2003
Bone Mineral Health of Indians: [PDF]
Bone mineral disorders in Indians can broadly
be divided into four categories: (i) osteo-porosis characterized
by low bone density and poor bone quality, predominantly age-related
or menopausal. It results in fragility fractures, of which hip
fractures are particularly devastating; (ii) osteomalacia and
rickets—disorders of mineralization, predominantly nutritional
(vitamin D deficiency) in origin. These result in bone softening,
deformity and fractures in children and adults; (iii) skeletal
fluorosis which results in poor bone quality due to environmental
(usually drinking water) fluoride toxicity. It often leads to
deformity and can be crippling, even in children; and (iv) less
common disorders such as primary hyperparathyroidism, hypophosphataemic
osteopathies, fibrous dysplasias, vitamin D-dependent rickets,
osteogenesis imperfecta and Paget disease. I will focus mainly
on the first of these, i.e. osteoporosis.
With increasing longevity of the Indian population, it is now
being realized that, as in the West, osteoporotic fractures are
a major cause of morbidity and mortality in the elderly. Osteoporosis
is a silent disease, reflected only in a low bone density, till
a fracture occurs. Much in the manner that asymptomatic conditions
such as hypertension and dyslipidaemia predispose to stroke and
myocardial infarction, respectively, a low bone density (reflecting
poor bone health) predisposes to osteoporotic fractures. During
puberty and adolescence, the skeleton takes up calcium avidly
and builds up its reserves. This uptake of calcium into the bone
is largely dependent on calcium and vitamin D nutrition, as well
as exercise. Peak bone mass is usually achieved by the age of
20 years. From the mid-thirties there is a gradual, progressive
bone loss, which continues throughout life and is accelerated
at the menopause in women. The fracture prevention strategy therefore
consists of increasing peak bone mass in the growing years and
reducing subsequent bone loss throughout life. Thus, the importance
of achieving and maintaining good bone health cannot be overemphasized.
Although reliable epidemiological data are lacking, hospital
data suggest that hip fractures are common in India. Data also
suggest that men are probably more commonly affected than women,
although this may be because the likelihood of men seeking hospital
attention is greater than that for women. Almost four decades
ago, Nordin reviewed 119 hip fractures and found that, in India,
they occur at all ages, with two peaks at 30–39 years and
again at 50–70 years. There was no attempt to distinguish
traumatic from fragility fractures.1 Around the same time, Gupta
et al. from Kanpur analysed 425 hip fractures, 63% of which were
in men. The average age at fracture was 55 years.2 Vaishnava
and Rizvi found osteoporosis based on iliac crest biopsies in
141 out of 421 hip fracture patients, and again more than half
their patients were men.3 Indians living in Singapore were also
found to have hip fractures at an average age of 58 years.4 More
recent data from Sankaran, involving 1393 patients of hip fractures
from 3 large Delhi hospitals, also indicate that these fractures
are common in both sexes, although the sex ratio in different
subgroups was variable, and not always in favour of men. The
peak age at which these fractures occurred was 60–70 years.5 In western countries, women suffering from osteoporosis far outnumber
men, and this is largely thought to be due to the effects of
the menopause. Some authors conclude that:6
1. osteoporosis is prevalent in India;
2. osteoporotic fractures occur more commonly in Indian men than
in women; and
3. in India, osteoporotic fractures occur 10–20 years earlier
than in the West.
While these are reasonable conclusions, we must keep in mind
that there are no epidemiological data on fracture prevalence,
although most clinicians would agree that hip fractures are common.
The men:women ratio may be distorted because men are more likely
to be brought for hospital care. The lower peak age as compared
to the West may simply be linked to a shorter life span, as also
to the inclusion of traumatic/non-fragility fractures in the
analysis. Perhaps it is best to conclude that osteoporotic fractures
are common in India and occur in both sexes.
Dual energy X-ray absorptiometry (DEXA) technology, the gold
standard for diagnosing osteoporosis by measuring bone density,
became available in India only in 1997 at the Sanjay Gandhi Post
Graduate Institute of Medical Sciences, Lucknow. Subsequently,
several other machines became available and the past 2 years
have seen their number grow to almost 100. These are still mostly
in the larger cities—Delhi and Mumbai alone account for
more than 20 of these installations. Thus, while certain segments
of the Indian population do have access to diagnosis and treatment,
these techniques remain inaccessible to the majority of Indians.
The most important question in this regard is the appropriateness
(or otherwise) of western standards for diagnosing osteoporosis
in Indians. Single-centre studies on bone mineral density (BMD)
in Indians (from Lucknow, Delhi, Bangalore, Chennai) using DEXA
have started appearing in the literature and have consistently
shown a lower BMD in Indian women. Overall, the BMD at all sites
seems to be 5%–15% lower than that in Caucasians.7–11
However, there are differences in BMD between different centres,
and a recent study involving healthy subjects presenting for
a preventive health check in Delhi has suggested that differences
with western populations in BMD may be minimal, and could be
related to the smaller skeletal size of Indians.12 Studies on
expatriate Indians, although on a limited number of subjects,
have also shown a lower BMD as compared to that in Caucasians.13,14 The issue of appropriate BMD normative data for Indians remains
open. There is a need to study the BMD–fracture relationship
in Indians (fracture threshold) to determine the ideal normative
data for the Indian population.15 If Indians fracture at the
same level of BMD as Caucasians, there would be no reason to
have separate normative data for Indians.
What could be the reasons for these differences in bone density?
Is it genetic? Or is it related to skeletal size? Both are likely
reasons. However, calcium and vitamin D nutrition plays an important
role in determining bone health. Recent data indicate a high
prevalence of vitamin D deficiency in urban Indians, despite
the availability of abundant sunshine. Studies have shown that
the majority of urban office workers and hospital staff have
moderate to severe vitamin D deficiency, which is usually asymptomatic.16,17 Arya et al. used a serum 25(OH) vitamin D level of 15 ng/ml as
a cut-off, and found 66.3% of subjects to be vitamin D deficient.
Of these, 20.6% had severe vitamin D deficiency (<5 ng/ml),
27.2% had moderate (5–9.9 ng/ml) while 18.5% had mild vitamin
D deficiency (10–14.9 ng/ml). When a serum 25(OH) vitamin
D level of 20 ng/ml was used as a cut-off, 78.3% subjects were
diagnosed to be vitamin D deficient/insufficient. The serum 25(OH)
vitamin D level correlated with sunlight exposure and femoral
neck BMD. Inadequate calcium intake was proposed as an additional
factor contributing to the low BMD. Thus, low vitamin D levels
(and low calcium intake) could also be major contributing factors
to poor bone health and osteoporosis in India.17
Poor sunlight exposure, skin pigmentation and a vitamin D-deficient
diet are some obvious causes for this finding. Atmospheric pollution
has also been suggested as a contributor to vitamin D deficiency
in children from Delhi.18 Low serum 25(OH) vitamin D levels have
also been reported in expatriate Indians from the UK and USA.12,19 Lo et al. showed that Indian and Pakistani immigrants in the
USA have the same capacity to produce vitamin D in response to
ultraviolet light though longer exposure to sunlight is required.20 One study reported altered vitamin D metabolism in cultured skin
fibroblasts from Indians.21
The spectrum of vitamin D deficiency in India extends from asymptomatic
deficiency, described above, to frank osteomalacia, a crippling
disorder, which continues to be seen, even in ‘tertiary
care’ corporate hospitals.22 Another reflection of the
poor bone health of Indians is the severe bone disease seen in
Indians with primary hyperparathyroidism, who have consistently
been shown to have low serum levels of 25(OH) vitamin D.23 Vitamin
D replete ‘western’ patients of primary hyperparathyroidism
typically have no symptoms at all and are diagnosed on routine
laboratory screening for serum calcium level.
In this issue of the Journal, Tandon et al. report their findings
on the bone health of Indians with optimal vitamin D availability.24 Their subjects were healthy young adults, both men and women,
from the Indian paramilitary forces. They consumed a nutritious,
balanced diet, with average calcium intakes of over 750 mg/day
in women and 1000 mg/day in men. They performed regular physical
exercise and had adequate exposure to sunlight. The authors report
a serum 25(OH) vitamin D level of 18.4 ng/ml in the subjects
studied in winter and 25.3 ng/ml in those studied in summer.
These levels are much higher than those reported in previous
studies from India, which is probably simply related to greater
exposure to sunlight in this study population. Although the sample
size is small, the differences in BMD as compared to western
controls were also less than those reported earlier. The BMD
of women was comparable at all sites, while the BMD of men was
different only at the lumbar spine. The minor differences in
BMD could possibly be related to lower peak bone mass attained
during puberty, since these subjects were recruited to the service
after 18 years of age. They could also reflect differences in
skeletal size. The study is of importance because it has shown
that a healthy lifestyle (diet, exercise and sunlight exposure)
can have a major positive impact on the bone metabolism and bone
health of Indians.
It appears that typical urban (‘white collar’) Indians
have poor bone health, and osteoporosis is common in India. However,
adequate calcium intake, regular physical exercise and exposure
to sunlight can go a long way in improving the bone health of
Indians and potentially reducing the risk of fracture. There
is thus an urgent need for greater public awareness in this regard,
particularly about the benefits of sunlight exposure.
Nordin BEC. International
patterns of osteoporosis. Clin Orthop 1966;45:17–30.
Gupta AK, Samuel KC, Kurian PM, Rallan
RC. Preliminary study of the incidence and aetiology
neck fracture in Indians. Indian J Med Res 1967;55:1341–8.
Vaishnava H, Rizvi SNA. Frequency
of osteomalacia and osteoporosis in fractures of proximal
femur. Lancet 1974;1:676–7.
Wong PCN. Femoral neck fractures
among major racial groups in Singapore: Incidence
pattern compared with new Asian communities.
Med J 1964;5:150–4.
Sankaran B. Clinical studies: Incidence
of fracture neck of femur and intertrochanteric fractures
three Delhi hospitals.
B (ed). Osteoporosis. New
Delhi:South East Asia Regional Office, World Health
Gupta A. Osteoporosis in India—the nutritional hypothesis. Natl
Med J India 1996;9:268–74.
Mithal A, Nangia S, Arya V, Verma
BR, Gujral RB. Spinal bone mineral density in normal
J Bone Miner
Reddy PG, Mithal A, Rao DS. Bone
mineral density in healthy Asian Indian women: Development
of a reference database and
implications for diagnosis of osteoporosis
in Indian women living in the United States
[abstract]. J Bone Miner
Res 2002;17 (Suppl 1):SA270.
Ravishankar U. Bone mineral density
in normal Indian women: Assessment by dual
B (ed). Osteoporosis.
East Asia Regional Office, World Health
Dharmalingam M, Prasanna Kumar KM,
Patil J, Karthikshankar S. Study
of bone mineral
women [abstract]. Bone 2003;32 (Suppl):S178.
Anburajan M, Rethinasabapathi
C, Korath MP, Ponnappa BG, Kumar
KS, Panickar TM,
et al. Age-related
loss in South Indian women:
A dual energy X-ray absorptiometry
study. J Assoc Physicians
Keramet A, Bhambhri R, Chakravarty
D, Mithal A. Spinal bone
mineral density in
for a preventive
[abstract]. J Bone Miner
Res 2003;18 (Suppl 1):SA083.
Alekel DL, Mortillaro
E, Hussain EA, West B,
Ahmed N, Peterson
CT, et al.
and biologic contributors
bone mineral density
and hip axis length in
two distinct ethnic groups of
Cundy T, Cornish J,
Evans MC, Gamble
G, Stapleton J,
Reid IR. Sources
in bone mineral density.
Miner Res 1995;10:368–73.
Usha G, Krishnaswamy
B. Bone mineral
elderly. J Assoc
Goswami D, Marwaha
N. Prevalence and
low 25 hydroxyvitamin
subjects in Delhi. Am
J Clin Nutr 2000;72:472–5.
R, Godbole MM,
A. Vitamin D
bone mineral density
Indians. Osteoporos Int
(in press) (online
Agarwal K, Upadhyay
Mawer EB, Berry
Mughal Z. The
vitamin D status
clinic. Bone 1999;25:609–61.
Endocrinol Metab 1998;83:169–73.
19–22, 2003: P-3/560 (abstract).
Miner Res 2002;17 (Suppl
Indian Society for Bone and Mineral Research
Department of Endocrinology
Indraprastha Apollo Hospitals